Anthropogenic disturbance in driving floating marine litter across three coastal interfaces

Floating marine litter (FML), due to its persistence and long-range transport potential, has significant impacts on the global marine environment and biodiversity. The coastal watershed interface is a major contributor to this issue, highlighting the importance of quantifying the impact of anthropogenic disturbance on FML for effective management. This study used year-round monthly monitoring data of FML and remote sensing data on land-based anthropogenic disturbance to assess its impact on FML in three representative zones: the watershed (WS), the intersection area between the watershed and coastal zone (IWCZ), and the intersection area of the watershed and coastal buffer zone (IWBZ), employing univariate (linear regression, correlation) and multivariate (CCA) analyses. The results indicate that IWBZ experiences the highest human activity pressure, with points of interest density (POID), impervious surface ratio (ISR), and population density (POPD) being 1.95, 1.76, and 1.74 times the peninsula's average, respectively. Anthropogenic disturbance impacts FML differently across the three zones, with the IWBZ showing the strongest effect (correlation coefficient = 0.89), while no significant correlations were found in IWCZ and WS. Among anthropogenic disturbance factors, POID has the strongest contribution to FML density, with a weighted importance of 53.03 % to 71.15 %, significantly higher than ISR and POPD. Tourism-related POIs correlate with FML density in all three zones, while residential POIs show stronger correlations in IWBZ and IWCZ than in WS. This study identifies key areas and anthropogenic disturbance factors for prioritization in coastal planning, offering insights for integrated research and evidence for sustainable management and resilient restoration.